This application is based on and claims priority to Japanese Patent Application No. 11-022,650, filed Jan. 29, 1999, the entire contents of which is hereby expressly incorporated by reference.
1. Field of the Invention
The present invention generally relates to an improved mechanism for controlling the speed of a personal watercraft. More particularly, the present invention relates to an improved throttle control system for a personal watercraft.
2. Description of Related Art
Personal watercraft are a relatively small sporty-type of watercraft wherein the rider sits or stands more on top of the watercraft than in other types of watercraft. Typically, a personal watercraft is designed to be operated by a single rider or operator, although accommodations are frequently made for one or more passengers.
Personal watercrafts are typically powered by an internal combustion engine. Fuel is supplied to the engine by charge formers, which can be carburetors or fuel injectors depending upon the application. Air is supplied to the engine by an air induction system. Located within the air induction system is one or more throttle valves that regulate the amount of air delivered to the engine. Because fuel flow is typically metered in proportion to the air flow, the throttle valves, in essence, control the power output of the engine and thus the speed of the watercraft as is well known in the art.
Personal watercraft typically include a handlebar that is mounted to an upper deck of the watercraft. The operator uses the handlebar to steer the watercraft. On the handlebars, near a grip, is a throttle lever. The throttle lever is typically directly coupled to the throttle valves by one or more cables. Accordingly, the operator controls the position of the throttle valves and thereby the speed the watercraft by moving the throttle lever.
The throttle valves are normally biased to an idling position by one or more return springs. Another spring biases the throttle lever back to an unactuated position that corresponds to the idle position of the throttle valves. In order to further open the throttle valves and increase the speed of the watercraft, the operator typically grasps the throttle lever with one or more of her fingers and moves the lever towards the handlebar grip. When the operator releases the throttle lever, the return springs force the throttle valves and the throttle lever back to the idling position. Therefore, in order to maintain the speed of the watercraft, the operator must hold the throttle lever at a specific position against the return force of the return springs. Furthermore, if the operator""s fingers slip, the throttle lever will return quickly to the idling position causing the watercraft to decelerate suddenly.
The prior art system for controlling the position of the throttle valves in a personal watercraft has several disadvantages. For example, to maintain the speed of the watercraft, the operator must hold the throttle lever against the force of the return springs. Accordingly, the operator""s fingers may become tired after holding the throttle lever only for awhile. Another problem with the prior art system is that if the operator suddenly lets go of the throttle lever the throttle valves quickly return to their idling position causing the watercraft to decelerate quickly. This sudden deceleration can cause the watercraft to suddenly slip from a planing state to a non-planing state.
Accordingly, one aspect of the present invention involves a personal watercraft comprising a hull and an internal combustion engine disposed within the hull. The engine includes an air induction system that supplies air to the engine and has a throttle device to regulate the amount of air supplied to the engine. A steering.mechanism steers the watercraft and includes a handlebar assembly coupled to the hull for this purpose. A throttle device control system includes a throttle operator that is located on the handlebar assembly and is arranged to be controlled by a rider of the watercraft. An operator position sensor is configured to detect the position of the throttle operator and to output a data signal that is indicative of the detected position of the throttle operator. A controller communicates with the operator position sensor to receive the data signal and is configured to output a control signal in response to the data signal. An actuator communicates with the controller. The actuator also is coupled to the throttle device and is adapted to adjust the throttle device in response to the control signal from the controller.
Another aspect of the present invention involves a personal watercraft comprising a hull and an internal combustion engine disposed within the hull. The engine includes an air induction system that supplies air to the engine and has a throttle device to regulate the amount of air supplied to the engine. A steering mechanism controls the steering movement of the watercraft and includes a handlebar assembly coupled to the hull. A throttle device control system includes a throttle operator that is located on the handlebar assembly and is arranged to be controlled by a rider of the watercraft. Means are provided for detecting a position of the throttle operator, and for moving said throttle device in response to the detected position of the throttle operator.
Further aspects, features, and advantages of the present invention will become apparent from the detailed description of the preferred embodiment which follows.